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In this paper, the variations of aerosol properties due to crackers burning during Diwali event (11th–18th 2012) over mega city Delhi were investigated. The sky radiometer POM-2 aerosol optical property data from Skynet-India along with ambient air pollution data were critically analyzed. The aerosol optical depth (AOD) at 500 nm was 1.60 on 13th November, the Diwali day, and its value a maximum of 1.84 on 16th November. Due to stable atmosphere over Delhi during post Diwali, aerosols accumulate and remain in the atmosphere for longer time, which leads to higher AOD on 16th November. A lower value of single-scattering albedo (SSA) was observed at a longer wavelength (1020 nm) during the entire period that clearly indicates the dominance of absorbing-type black carbon aerosol. SSA showed a steep decrease after 16th November. Asymmetry parameter decreased to a maximum of 0.79 for the shorter wavelength at 340 nm and 0.632 is reported at the higher wavelength 1020 nm. Asymmetry parameter showed a decrease in value just after Diwali on 14th November, this suggesting the dominance of fine-mode aerosol from anthropogenic activities. The lowest value of the refractive index (1.4527) on 14th and 15th November indicates the higher loading of absorbing-type aerosol which may be associated with firecracker burning of Diwali festival. The significant correlation with the value of r = 0.9 was observed between sky radiometer and MODIS AOD with a standard deviation of 0.31 and an RMSE of 0.17 during the event. Radiative forcing and heating rate were estimated using SBDART. The maximum average concentrations 2641 and 1876 μg/m³ of PM10 and PM2.5, respectively, were observed on the Diwali night. A highest of 109 ppb surface ozone was reported in the night at 23:00 IST, which can be attributed to burning of the firecrackers.
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Earth Systems and Environment
Eect ofDiwali Firecrackers onAir Quality andAerosol Optical
Properties overMega City (Delhi) inIndia
M.Sateesh1· V.K.Soni2· P.V.S.Raju1
Received: 11 February 2018 / Accepted: 29 May 2018
© Springer International Publishing AG, part of Springer Nature 2018
In this paper, the variations of aerosol properties due to crackers burning during Diwali event (11th–18th 2012) over mega
city Delhi were investigated. The sky radiometer POM-2 aerosol optical property data from Skynet-India along with ambi-
ent air pollution data were critically analyzed. The aerosol optical depth (AOD) at 500nm was 1.60 on 13th November, the
Diwali day, and its value a maximum of 1.84 on 16th November. Due to stable atmosphere over Delhi during post Diwali,
aerosols accumulate and remain in the atmosphere for longer time, which leads to higher AOD on 16th November. A lower
value of single-scattering albedo (SSA) was observed at a longer wavelength (1020nm) during the entire period that clearly
indicates the dominance of absorbing-type black carbon aerosol. SSA showed a steep decrease after 16th November. Asym-
metry parameter decreased to a maximum of 0.79 for the shorter wavelength at 340nm and 0.632 is reported at the higher
wavelength 1020nm. Asymmetry parameter showed a decrease in value just after Diwali on 14th November, this suggesting
the dominance of fine-mode aerosol from anthropogenic activities. The lowest value of the refractive index (1.4527) on 14th
and 15th November indicates the higher loading of absorbing-type aerosol which may be associated with firecracker burning
of Diwali festival. The significant correlation with the value of r = 0.9 was observed between sky radiometer and MODIS
AOD with a standard deviation of 0.31 and an RMSE of 0.17 during the event. Radiative forcing and heating rate were
estimated using SBDART. The maximum average concentrations 2641 and 1876μg/m3 of PM10 and PM2.5, respectively,
were observed on the Diwali night. A highest of 109ppb surface ozone was reported in the night at 23:00 IST, which can
be attributed to burning of the firecrackers.
Keywords AOD· Air pollution· PM2.5· MODIS and HYSPLIT back trajectory
1 Introduction
In recent years, concerns for atmospheric aerosols have been
increased due to their adverse effects on regional air qual-
ity, human health, weather, and climate. Numerous studies
have been carried out to assess the anthropogenic aerosols
especially in densely populated mega cities. During the
recent time, firing cracker is getting popularity especially
in urban regions which leads to substantial air pollution and
degradation of visibility (Singh etal. 2015). The burning of
crackers is a major source of pollution in India during Diwali
festival (Pervez etal. 2016; Pongpiachan etal. 2017). Fire-
crackers emit a huge amount of gaseous pollutants such as
carbon monoxide, ozone, sulfur dioxide, and nitrogen oxides
(Attri etal. 2001). Burning of firecrackers also release a
large quantity of particulate matter along with several metal
salts (such as Pb, Cd, V, Ni, Cu, Zn, Mn, and Fe) into the
atmosphere, which forms dense clouds of smoke containing
various toxic compounds (Kulshrestha etal. 2004; Pöschl
2005; Aksu 2015). The studies on elevated concentrations
of pollutants during celebrations with firecrackers are very
few in Indian context (Barman etal. 2008; Chatterjee etal.
2013; Darga etal. 2006; Devara etal. 2015; Simha etal.
2013). Firecrackers cause acute short-term air quality deg-
radation (Barman etal. 2008), but long-term effects on
regional climate (Ramanathan and Feng 2009), long- and
short-term effects on human health (Godri etal. 2010), and
also visibility reduction (Clark 1997). A recent study on
UK Guy Fawkes Nights affected the visibility during the
* P. V. S. Raju;
1 Centre forOcean-Atmospheric Science andTechnology,
Amity University Rajasthan, Jaipur, India
2 India Meteorological Department, Lodi Road, NewDelhi,
M.Sateesh et al.
1 3
festival period (Singh etal. 2015). The higher wind speeds
will washout/drifted the aerosol concentrations, clear sky
conditions increases the planetary boundary layer in the
noon time, and the higher relative humidity conditions will
produce hazy conditions in the early morning hours. The
inverse relation between RH and visibility will affect the
optical properties of aerosol (Singh etal. 2017). The sur-
face ozone concentrations are proportional to temperatures
where as these ozone concentrations are high in the night
time also in the presence of NO2, NO, and florescence emit-
ting firecrackers.
The urban air database released by the World Health
Organization in September 2011 reported that Delhi has
already exceeded the maximum PM10 limits. The increase
of PM10 and PM2.5 is affecting the human health in terms
of respiratory problem which leads to chronic diseases
(Nidhi and Jayaraman 2007) over high dense metropolitan
cities such as National Capital Regions (NCR), India. This
becomes a serious issue in the point of public health; the
government of India has taken an initiative to ban firecrack-
ers in and around the NCR to prevent the usual spike in toxic
air pollution levels. Aerosolsare tiny particles suspended in
the atmosphere and exhibit a range of sizes depending on the
source of production (smoke particles, dust, fog, etc.). These
particles are responsible for scattering or absorption of solar
radiation within the atmosphere. The characterization of the
spectral dependence of AOD in the atmosphere is imperative
for modeling of the radiative effects of aerosols (Ali etal.
2017; Eck etal. 1999).
Diwali is one of the historical festivals celebrated in India
during the post monsoon season of October/November every
year. During the Diwali festival, millions of people light
traditional lamps and burn firecrackers especially in north
India. The firecrackers are low intensity explosive pyro-
technic devices which can be classified as handheld, ground
based, and aerial firecrackers. It is normally celebrated for
three consecutive days. The preparations for festival cel-
ebrations start by burning firecrackers a few days before the
Diwali and reach an upsurge on the Diwali day. The fire-
crackers continue after Diwali for few more days. During the
year 2012, the main day of Diwali was on 13th November.
In this paper, we have presented variations in aerosol
characteristics from satellite remote sensing measurements
and ground-based observation during the Diwali festival
period 11th–18th November 2012. The temporal variations
of gaseous pollutants, solar-radiation flux, and meteoro-
logical parameters were also studied. Correlation of these
elevated perturbations in aerosol parameters with other
plausible meteorological parameters and effects on radiative
forcing were discussed. The main reason for selecting 2012
Diwali is prevailing cloud-free sky that during the period
is ideal case to investigate the aerosol optical properties in
detail. However, the aerosol concentrations are high in the
cloudy conditions as compared to the cloud-free conditions
due to the lowering of PBL which can be examined by the
active sensors such as Lidar, CALIPSO observations (Deng
etal. 2016). The CALIPSO observations on these Diwali
days over Pune region also show an increase of back scatter
coefficient at 5km (Devara etal. 2015).
The present study will help understand the effect of acute
transient air pollution episode and further improves air qual-
ity predictions, as currently available models do not incorpo-
rate the air pollution data arises from the firecrackers under
cloud-free condition.
2 Data andMethodology
Delhi is the national capital territory of India, located
between the latitudes of 28o 24`–28o 53`N and longitudes
of 76°50–77o 20E, (218m, AMSL), having an area of 1483
km2. Delhi is considered as one of the most polluted urban
regions, lies in the Indo-Gangetic plain where anthropogenic
activities are more. The air quality in November month is
poor over northern parts of India due to the extreme crop
residue burning episodes along with vehicular and indus-
trial pollution. The winds from the north-west direction will
bring the smoke to the Indo-Gangetic plain; furthermore,
it affects the air quality and visibility (Dumka etal. 2016;
Kharol etal. 2012; Mor etal. 2017).
Sky radiometer (POM-02), an automatic sun-tracking
equipment capable of measuring direct solar and diffuse sky
irradiance at different spectrums ranging from ultra violet
region to near Infrared region, is used for the measurement
of aerosol optical properties in Delhi. The columnar aero-
sol optical parameters such as aerosol optical depth (AOD),
single-scattering albedo (SSA), and asymmetry parameter
(ASY) are derived from the sun/sky irradiance measure-
ments at seven wavelengths, i.e., 315, 400, 500, 675, 870,
940, and 1020nm using Beer–Lambert law. More details
of instrument configuration, data collection, calibration,
and inversion algorithms of sky radiometer are provided
in (Nakajima etal. 1996). The time series of optical and
physical properties of columnar aerosol is discussed dur-
ing the Diwali event. The Aqua satellite-based MODIS 3k
aerosol product (MYD04_3K) at 550nm (Nichol and Bilal
2016) has also been used for comparison studies over Delhi.
The daytime averaged aerosol optical depth (AOD) meas-
ured by the sky radiometer (POM-II) is compared with the
MODIS-3km (MYD04_3K) satellite data over Delhi region
to find the temporal correlation during the period.
In general, the aerosol particle distribution categorized
into three types based on their size are nucleation (Aitken)
mode (particle diameter < 0.1 µm), a fine/accumulation
mode (particle diameter: 0.1µm < d < 1µm), and a coarse
mode (particle diameter d > 1µm) (Bisht et al. 2015). The
Effect ofDiwali Firecrackers onAir Quality andAerosol Optical Properties overMega City (Delhi)…
1 3
spectral dependence of AOD has been used to derive aerosol
volume size distribution in the vertical column of the atmos-
phere using inversion algorithm (Nakajima etal. 1996). The
observed aerosol columnar volume size distribution is found
to be a bimodal lognormal function represented by
where Vo denotes the particle volume concentration, rm is the
median radius, and σ is the standard deviation.
PM10 and PM2.5 concentrations were monitored using
Beta Attenuation Monitor (BAM-1020), which employs the
principle of beta-ray attenuation. Surface ozone concen-
tration was measured with a UV ozone photometer model
Thermo-49i. Concentration of NO and NOx was measured
with chemiluminescence NOx analyzers model Thermo-42i.
Carbon monoxide(CO) in ambient air was measured using
the gas filter correlation method by CO Analyzer Model
Thermo-48i. A detailed description of monitoring methods
and site locations is also available in Parkhi etal. (2016),
and these instruments are well calibrated on real time to give
public awareness (http://safar .tropm The meteoro-
logical data presented in this study were obtained from India
Meteorological Department.
3 Results andDiscussion
The aerosol loading in the atmosphere is significantly
influenced by the meteorological conditions (Shaw 1988).
Figure1a represents the average daily variations of mete-
orological parameters such as air temperature (°C), rela-
tive humidity (%), pressure (hPa), and wind speed (kmph)
during Diwali festive period. The daily average tempera-
ture, relative humidity, and pressure varied from 16–20°C,
55–78%, and pressure range (1014–1017) hPa, respec-
tively, over Delhi during Diwali period (Fig.1a). The daily
average temperature reported lowest on Diwali day (13th
November) with minimum value of 16.3°C. It is further
increased to 17.3°C on 14th November. The daily aver-
age relative humidity started increasing from 11th Novem-
ber and reached a maximum of 78% on 12th November,
after that RH showed decreases till 15th November. The
high RH during these high pollution episodes leads to the
reduction of visibility by changing its optical properties
(Singh etal. 2015, 2017). Prior to Diwali, slightly lower
wind speed is observed, whereas the higher wind speed was
observed during Diwali and post Diwali period. But there is
an abrupt decrease in wind speed on 16th November, which
leads to calm condition and stable atmosphere. The diurnal
d ln
variations of outgoing terrestrial radiation from 11th to 18th
November over Delhi are depicted in Fig.1b. The diurnal
variation of solar radiative flux measured at every 10min
interval using pyranometer was higher (366Wm−2 day−1)
compared to other days (260–290Wm−2 day−1).
3.1 Spectral Variations ofAOD
Figure2a depicts the daily spectral variations of mean AOD
during the Diwali festival period over Delhi. The vertical bar
signifies the standard deviation of the daily mean AOD at
each wavelength. The mean AOD at 500nm measured from
sky radiometer depicts lesser value 0.75 on 18th November
2012, demonstrating that the atmosphere was relatively less
on that day compared to other days of festive period. AOD
increases from the prior to the Diwali. Since people start
burning firecrackers about 2 days prior to the Diwali day and
after 2 days especially in urban cities (Singh etal. 2004). On
13th November, the Diwali day AOD at 500nm was 1.60
and it reached to a maximum value of 1.84 on 16th Novem-
ber (Fig.2a). Spectral variability in AOD showed decreases
with increasing wavelength during the whole study period.
Highest values of AOD at all wavelengths were observed on
16th November which clearly indicates the higher aerosol
loading after the festival. The loading of airborne trace met-
als is the main reason to increase AOD in the festival peri-
ods. A study carried by Kulshrestha etal. (2004) reported
that Ba, K, Al, and Sr increase to 1090, 25,18, and 15 times,
respectively, to the previous Diwali day over a coastal site
Ground-based measurements of AOD at 500nm is
extrapolated to obtain AOD at 550nm (Ali etal. 2017; More
etal. 2013) as per the mentioned formula (1) and compared
with MODIS-derived values
From Fig.2b, nearly similar tendency was observed in
the MODIS/AQUA AOD at 550nm. The difference in the
observations is because MODIS data are at a specific time
and spatially averaged, while sky radiometer data are point
measurements. MODIS daily AODs at 550nm were noticed
in the range 0.43–1.44 during Diwali. The AOD at 550nm
was ~ 1.35 on the main Diwali day. MODIS AOD showed
good agreement with sky radiometer-derived AOD. Fig-
ure2c is the Taylor diagram showing correlation coefficient
of 0.9 and centered root-mean-square error of 0.17 between
MODIS AOD and sky radiometer measured AOD. The
standard deviation of sky radiometer observed AOD is 0.37.
Figure 3a exhibits a distinct bimodal distribution
similar to lognormal curves during Diwali period. The
bimodal nature of the aerosol volume size distribution can
be attributed to aerosols from a combination of different
550 =𝜏500
[550 nm
500 nm ]𝛼
M.Sateesh et al.
1 3
sources in the atmosphere (Hoppel etal. 1985). In gen-
eral, the primary peak represented by the concentration
of fine- and accumulation-mode particulates is due to the
anthropogenic activities (Devara etal. 2015) and gas phase
to particle reaction products (Singh etal. 2004). The sec-
ondary peak represents coarse-mode particles from natural
sources such as wind blown dust (More etal. 2013). Fig-
ure3a reveals that the fine-mode concentration was more
after the Diwali period from 14th to 16th November 2012.
This indicates the influence of smaller particles emitted
from the Diwali firecrackers. After Diwali on 14th Novem-
ber 2012, there is high volume of fine-mode aerosol while
a very low volume of coarse-mode aerosol clearly indi-
cates the dominance of firecrackers burning fine-mode aer-
osols. The higher fine-mode concentration was observed
on 16th November 2012, whereas the lowest concentration
of fine particles was reported on 18th November 2012.
Table1 shows the parameters of the accumulation- and
coarse-mode radii of the aerosol columnar volume size
distribution and corresponding values of the Angstrom
exponent and turbidity coefficient. From Fig.3a, we per-
ceive that the fine-mode peak concentrations of aerosol
particles range from 0.01 to 0.14µm with corresponding
mean radius around ~ 0.5µm, while coarse-mode aerosol
particles are 1.1–10µm with corresponding mean effective
radius as ~ 5µm (Table1). Nevertheless, in comparable
studies, the magnitudes of coarse-mode peak volume con-
centration are slightly greater than fine-mode peak volume
concentration during Diwali period.
Fig. 1 a The daily averaged
meteorological parameters and
b diurnal variation of the outgo-
ing terrestrial radiation
Effect ofDiwali Firecrackers onAir Quality andAerosol Optical Properties overMega City (Delhi)…
1 3
3.2 Aerosol Size Distribution
Angstrom exponent provides useful information on colum-
nar aerosol size distribution and can be derived from spec-
tral dependence of AOD at different wavelengths by fitting
an Angstrom’s power law (Angstrom 1964)
is AOD, β is turbidity coefficient which is equiva-
lent to the AOD measured at 1μm, and it vary 0–0.5; higher
value of turbidity coefficient indicates higher aerosols load-
ing (McCartney and Hall 1977). α is the Angstrom exponent
and its value varies from greater than 2.0 for accumulation-
mode fresh smoke particles to nearly zero for high AOD
desert dust events dominated by coarse-mode particles
(Kaufman etal. 1992). The variations of α and β are shown
in Fig.3b. Higher α values indicates abundance of smaller
particles, and relatively higher β implying more extinction
is observed during 12th–14th November, when firecracker
activities are at maximum. The observed magnitude of Ang-
strom exponent and turbidity coefficient was in the ranges
0.97–1.02 and 0.82–0.83, respectively, during 12th–14th
Fig. 2 a Spectral AOD observed from sky radiometer. b Scat-
tered plot between observed AOD and the MODIS-derived AOD
at 550 nm. c Taylor diagram for the MODIS and sky radiometer
observed AOD at 550nm during Diwali period
Fig. 3 a Volume size distribution and b time series of alpha and beta
M.Sateesh et al.
1 3
SSA is a fraction of the aerosol light scattering over the
extinction, and it is a crucial variable in assessing the radia-
tive effects of aerosols (Dubovik and King 2000; Jacobson
2000). For radiative forcing estimates, the top of the atmos-
phere (TOA) forcing strongly depends on SSA values (Take-
mura and Nakajima 2002). SSA characterizes the combined
effect of scattering and absorption properties of aerosols.
The spectral dependence of scattering coefficient is attrib-
uted to the size of particles and the absorption coefficient to
chemical composition of the particles. Thus, SSA is mostly
dependent on the size distribution and chemical composition
of aerosols.
Figure4a displays the variation of spectral SSA during
the Diwali period. It is observed that SSA decreases with
wavelength having a value of 0.95 at 380nm and 0.93 at
1020nm on 14th November 2012. Lower SSA at longer
wavelength shows higher concentrations of absorbing-type
black carbon aerosol, which is attributed to the presence of
a mixture of aerosols from Diwali firecrackers. The higher
change in SSA after the Diwali can be due to the prevailing
meteorological conditions and the background urban aerosol
The asymmetry parameter (g) is a representation of
cosine of the scattered angle for the scattered radiation and
is a very sensitive optical property to controlling the aerosol
radiative forcing. The variation of g with wavelengths is a
representation of the angular scattering, and it depends on
the size and composition of the particles. The value of g
ranges between − 1 for entirely backward scattered radiation
and + 1 for entirely forward scattered radiation. The scat-
tering of the light by aerosols occurred when the size of the
particle is higher than the wavelength of interacting radia-
tion; most of the radiation will get scattered in the forward
direction (0 to + 1) and vice versa. The asymmetry factor
varies with wavelengths due to that the sizes of aerosols
are comparable with wavelengths of interacting radiation.
Figure4b shows temporal variations of daily asymmetry
parameter during Diwali festival 2012. The mean asymmetry
factor during the period had a value varied from 0.68 ± 0.03
to 0.73 ± 0.04 at 500nm. The 340, 870, and 1020nm-based
asymmetry parameters are showing minimum value on 14th
November 2012, but the rest (i.e., 500, 675, and 400nm)
are showing on 13th November 2012. Lower value of g on
14th November is corresponding to dominance of fine-mode
aerosol due to firecrackers burning during Diwali.
The size and chemical compositions of aerosols present
in the atmosphere are important components for estimating
the radiative effects of the aerosols. The refractive index
(RI) is the best representation of the chemical composition
of aerosols or absorbing type of aerosols (Torres etal. 1998)
described by combining real n(λ) and imaginary k(λ) parts.
The real part n(λ) denotes the scattering which leads to cool-
ing while the imaginary part k(λ) enumerates the nature of
the absorption which leads to warming of the atmosphere
(Zarzana etal. 2012). In the present study, the refractive
index of aerosols is derived using sky radiometer (Nakajima
etal. 1996). The temporal variations of real and imaginary
parts of the refractive index [n(λ) and k(λ)] at 380nm which
has strong absorption of UV rays are shown in Fig.4c. The
n(λ) and k(λ) at 380nm were 1.4527 and − 0.0061, respec-
tively, on 14th November 2012. The k(λ) decreased sharply
from 13th to 14th November which implies that the absorp-
tion particles are dominant than the scattered particles. Thus,
the aerosol particles emitted during the Diwali festival are
more absorbing in nature, which was also confirmed from
SSA values observed during festival period.
3.3 Long‑Range Transport ofAerosols
Air mass back trajectories are often used to investigate
the possible transport pathways of trace gases and atmos-
pheric aerosols (White etal. 2006). These back trajecto-
ries are primarily intended from the observed meteorologi-
cal fields. In this study, back trajectories are derived from
Table 1 Volume concentration and effective radius of fine- and coarse-mode particles during Diwali event
Angstrom exponents and turbidity coefficient are also presented
Fine mode Coarse mode Alpha Alpha (SD) Beta Beta (SD)
Volume con-
R (μm) SD Volume con-
R (μm) SD
11th November 0.036 0.611 0.005 0.080 5.448 0.027 0.915 0.0341 0.6893 0.1705
12th November 0.045 0.581 0.005 0.087 5.301 0.027 0.974 0.0301 0.8388 0.0519
13th November 0.044 0.544 0.005 0.061 5.194 0.027 1.023 0.037 0.8199 0.1751
14th November 0.040 0.467 0.004 0.037 4.965 0.026 0.998 0.0334 0.8261 0.0906
15th November 0.048 0.486 0.005 0.043 4.956 0.026 0.913 0.0242 0.9799 0.1004
16th November 0.050 0.506 0.005 0.050 5.010 0.026 0.877 0.0232 1.0345 0.1866
17th November 0.032 0.556 0.005 0.052 5.411 0.027 0.919 0.0384 0.6220 0.1297
18th November 0.023 0.637 0.006 0.046 5.087 0.026 0.994 0.0481 0.3786 0.0719
Effect ofDiwali Firecrackers onAir Quality andAerosol Optical Properties overMega City (Delhi)…
1 3
National Oceanic and Atmospheric Administration Hybrid
Single-Particle Lagrangian Integrated Trajectory (NOAA
HYSPLIT) version 4 model (Draxler 1998). Figure5 shows
5-day back trajectories over Delhi. A close examination of
these trajectories demonstrated that all the air masses have
their origin mostly over the northern states of Haryana,
Punjab, Himachal Pradesh, and Pakistan, where the highest
biomass burning occurs during November. The biomass
burning aerosols also significantly influenced the observed
AOD during Diwali period. Images taken from MODIS
Terra showed the hazy atmospheric conditions due to bio-
mass burning and Diwali firecrackers over Delhi (Fig.5d–f).
High levels of pollution found over Delhi during Diwali
were due to not only the local emissions from firecrackers,
but also long-range transport of pollutants from Diwali fire-
crackers as well as biomass burning.
As the data sample size is small and the observations are
limited to daytime only, segregation of increase in aerosol
loading due to local meteorology, long-range transport, and
Diwali festival activity is not possible in the present analy-
sis. Figure6 shows the MODIS (MYD04_3k) Dark Target
Deep Blue-derived AOD (Nichol and Bilal 2016) values
over northern parts of India. The high AOD was observed
over north-west part of India. The widespread increase in
AOD values was observed on 12th and 13th November 2012.
During the October and November months, biomass (mainly
crop residue) burning is reported in northern parts of India.
The increase in AOD and other pollutants has been reported
by researchers due to the crop residue burning in the north-
western parts of India (Badarinath etal. 2010; Bisht etal.
2015; Sharma etal. 2010). The widespread higher AOD val-
ues on 13th and 14th November over north-west part of India
are due to firecrackers in addition to the effect of biomass
The time series of PM concentration (PM2.5 and PM10)
at various locations in national capital city of Delhi is
depicted in Fig.7. The unprecedented rise in the PM2.5
concentration values during the Diwali indicates the increase
in the fine-mode particles in the atmosphere contributed by
firecrackers. The concentration of PM10 also showed signifi-
cant rise at all the location during Diwali event. The incre-
ment in the particulate matter during Diwali contributes to
rise in AOD, which lasts for several days after the festival till
16th November 2012 (Fig.7a, b). Furthermore, the signifi-
cant increase of NOx, NO2, CO, and O3 at various locations
over Delhi is also observed during Diwali period (Fig.8).
The secondary pollutant, surface ozone, is produced in
the presence of nitrogen oxides and sun light. Significant
increase in surface ozone concentration was observed in
the absence of sunlight (night time) during Diwali. The
color emitting due to firecrackers burning will give light
which can react with NO during the night time Diwali
period to produce O3. A strong correlation of 0.993 is
found during the Diwali nights with O3 and NO in the
presence of firecrackers (Attri etal. 2001). A highest
concentration of 109ppb was reported during night time
at 23:00 IST, whereas the NOx and NO2 were 63.7 and
23.2ppb, respectively, on 14th November 2012 (Fig.9).
An average of 38ppb is reported during the 18:00 IST
Fig. 4 Variation of a single-scattering albedo, b asymmetry param-
eter, and c refractive index during the Diwali period. The vertical bars
denote the 1σ standard deviation from the mean values
M.Sateesh et al.
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(evening) to the next day morning 06:00 IST. When the
firecrackers are burnt, a considerable proportion of light
is radiated by its constituents in wavelength 240nm which
helps in producing surface ozone. Figure9 shows two clus-
ters, which may be due to the dependence of production
of ozone with weather parameters or any other secondary
gases. It can be resolved by considering a large number of
observation points and detailed analysis in future studies.
3.4 Aerosol Radiative Forcing
SBDART is a plane-parallel radiative transfer model (Ric-
chiazzi etal. 1988), used in various atmospheric studies by
scientific communities for estimation of ARF. The param-
eters used as inputs in SBDART are AOD, SSA, Angstrom
exponent, asymmetry parameter, and atmospheric profiles.
In present, the daily mean values of AOD, SSA, and ASP at
500nm wavelength from sky radiometer are used as inputs
Fig. 5 5-day HYSPLIT back trajectory at three different altitudes
500 m (red color), 1500 m (blue color), and 2500 m (green color)
during Diwali period a 12th November 2012, b 13th November 2012,
c 14th November 2012 over Delhi. Modis (Terra images), d 12th
November 2012, e 13th November 2012, and f 14th November 2012
Fig. 6 a MODIS-3K AOD on 12th November 2012. b MODIS-3K AOD on 13th November 2012. c MODIS-3K AOD on 14th November
Effect ofDiwali Firecrackers onAir Quality andAerosol Optical Properties overMega City (Delhi)…
1 3
to SBDART model. For accurate estimation of ARF, an
input of surface albedo is an important parameter which
was calculated using the MODIS satellite generated black-
sky albedo (BSA) (direct reflectance) and white-sky albedo
(WSA) (bi-hemispherical reflectance) at short wavelength
spectral bands. Based on BSA and WSA at different solar
zenith angles, the actual albedo was calculated as given
where DSF is diffuse sky fraction (DSF) which is a function
of solar zenith angle and aerosol loading. The observed aver-
age AOD at its solar zenith angle has been used to derive DSF
available from MODIS land team (Schaaf etal. 2002). MODIS-
derived perceptible water content and OMI-derived total col-
umn ozone were also used as input parameters to SBDART.
In this study, ARF was calculated at the surface (SUR),
top of the atmosphere (TOA), and within the atmosphere
Actual Albedo =WSA DSF +BSA(1DSF),
up]with aerosol
up]without aerosol .
The net flux is difference of downward flux (Fdown) and
upward flux (Fup). The SBDART model computations are
estimated at 30-min intervals on each day and daily average
ARF values are estimated for TOA, SUR, and ATM.
Figure10 shows the temporal variation in ARF along
with the standard deviations obtained over Delhi during
Diwali festive period. From Fig.10, it is clear that during
Diwali period, the SUR has negative forcing (cooling) while
the ATM has positive forcing (warming). The average ARF
for the entire period of observations at the surface was − 53
Wm−2 and at top of the atmosphere was − 26Wm−2, giving
rise to an atmospheric forcing of about + 27 Wm−2. ARF
values observed over Kanpur (Kaskaoutis etal. 2013) at the
SUR (− 69 to − 97 Wm−2), TOA (− 20 to 30 Wm−2), and
ATM (+ 43 to 71 Wm−2) were less than the value observed
over in the present study. The ARF values on Diwali day,
i.e., 13th November 2012 at SUR, TOA, and ATM were
61, − 30, and 31 Wm−2, respectively. The average heating
rate of 1.8°C/day was estimated for study period. The higher
atmospheric heating in Diwali days is mainly due to low-
ered SSA associated with the Diwali firecrackers activities.
The ARF values clearly indicate the substantial reduction
in solar-radiation reaching Earth’s surface and heating of
the atmosphere during the period of the festival celebra-
tions. Similar results of higher atmospheric heating with
additional warming is observed as + 12 Wm−2 during fire
crackers burning over Varanasi (Singh etal. 2014).
4 Conclusions
The aerosol properties and its distribution depend on the
type of pollutant present in the atmosphere. The combina-
tion of biomass burning and the firecrackers impact fine-
mode particles in the atmosphere on the Diwali day, and
coarse-mode particles are more after the Diwali day. Higher
aerosol loading was observed after Diwali with maximum
value on AOD (1.84) on 16th November at 500nm; this
clearly indicates the effect of crackers burning. Asym-
metry parameter showed decreasing pattern from shorter
to longer wavelength during the entire study period with
minimum value on 14th November. Volume size distribu-
tion showed a dominance of the fine-mode particles after
the Diwali period from 14th to 16th November 2012, sug-
gesting the more contribution of fine-mode particles emitted
from the Diwali firecrackers. The air quality observations
reveal the significant rise of ozone levels in the during night
time which can be attributed to burning of firecrackers. The
increment of PM2.5 and PM10 during the festival time con-
tributes to the rise of optical parameters such as AOD and
also warming in the atmosphere. The ARF values on Diwali
day, i.e., 13th November 2012 at SUR, TOA, and ATM were
61, − 30, and 31 Wm−2, respectively. The average heating
Fig. 7 Time series of a PM2.5 and b PM10
M.Sateesh et al.
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Fig. 8 Time series of air quality measurements over various location in New Delhi for a NOx, b NO2, c CO, and d O3
Fig. 9 NOx vs. NO2 by levels of ozone
Fig. 10 Aerosol radiative forcing at surface, top of the atmosphere,
and atmosphere during Diwali festival period
Effect ofDiwali Firecrackers onAir Quality andAerosol Optical Properties overMega City (Delhi)…
1 3
rate of 1.8°C/day was estimated for the study period. The
maximum average concentrations of PM10 and PM2.5 on
Diwali night were observed as 2641 and 1876μg/m3. It is
also revealed that due to the burning of firecrackers, a high-
est amount of surface ozone (109ppb) was perceived on
13th November at 23:00 IST. The anthropogenic activities
during the Diwali period clearly illustrate drastic changes
in aerosol optical and physical properties in a metropolitan
city of NCR that can be directly effect on public health and
radiative effects.
Acknowledgements The authors sincerely thank Dr. K. J. Ramesh,
Director General of Meteorology, India Meteorology Department, for
encouraging to carryout this work. We also acknowledge NOAA and
NASA for providing online HYSPLIT back trajectory model and the
MODIS L2 AOD products. We thank three anonymous reviewers for
their constructive comments and suggestions which help us for further
improvement in the manuscript.
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... Reduced pollution caused by green crackers can be attributed to the replacement of harmful compounds like potassium nitrate and barium nitrate and metals like lithium, antimony, arsenic, mercury by their lesser polluting alternatives like copper and nitrogen-bearing compounds (Steinhauser and Klapötke 2008). The impact of firecrackers on air quality during Diwali has been studied by different authors in many parts of India (Kotnala et al. 2021;Sateesh et al. 2018;Parkhi et al. 2016;Chatterjee et al. 2013;Thakur et al. 2010). During this time duration, an abrupt deterioration of urban air quality due to the bursting of firecrackers and consequent increase in carbon monoxide, carbon dioxide, and other pollutant levels can be witnessed. ...
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Urban air pollution is a growing menace leading to human discomfort, increased hospitalizations, morbidity, and mortality. This study deals with deteriorated air quality due to firecracker bursting during Diwali in Lucknow. Inhalable particulates and gaseous pollutants were monitored during Diwali 2020 using air samplers. Elements, ions, and surface morphology of particles were analyzed using ICP-MS, ion chromatograph, and SEM-EDX, respectively. PM10, PM2.5, SO2, and NO2 were 558, 352, 44, and 86 μg/m³ during Diwali night and 233, 101, 17, and 40 μg/m³ on pre-Diwali night while 241, 122, 24, and 43 μg/m³ on Diwali day. Concentrations surged for PM10: 139% and 132%, PM2.5: 249% and 189%, SO2: 159% and 83%, and NO2: 115% and 100% on Diwali night compared to pre-Diwali night and corresponding Diwali day, respectively. Al, K, Ba, and B showed dominance in PM10 whereas Zn, Al, Ba, and K in PM2.5 on Diwali night. The order of metal abundance in PM2.5 was Cd < Co < Ag < As < Cr < Ni < Cu < Bi < Pb < Mn < Sr < Fe < B < Zn < Al < Ba < K. Cations NH4⁺, K⁺, Mg²⁺, Ca²⁺, and anions F⁻, Cl⁻, NO3⁻, Br⁻, NO2⁻, SO4⁻², PO4³⁻ showed a 2–8 fold increase on Diwali night relative to pre-Diwali night. Average metal concentrations varied by 2.2, 1.6, and 0.09 times on Diwali than pre-Diwali in residential, commercial, and industrial areas, respectively. PM10 concentration increased by 458% and 1140% while PM2.5, 487%, and 2247% than respective NAAQS and WHO standards. Tiny firecracker particles vary in toxicity as compared to vehicular emissions and have enhanced bioavailability leading to severe threat in terms of LRI, COPD, and atherosclerosis for city dwellers. It is imperative to recognize the present status of ambient air quality and implement regulatory strategies for emission reduction. Graphical abstract
... Carbon monoxide (CO) also plays a significant role in the oxidizing capacity of lower atmosphere by acting as a sink when large amount of reactive hydroxyl (OH) radical available in the troposphere (Ghude et al., 2011;Logan et al., 1981;Zahn and Brenninkmeijer, 2003). Biomass burning, Oxidation of methane, emission from fossil or bio fuel combustion and nonmethane hydrocarbon (NHMC) are the major source of emission of CO (Gore et al., 2014;Marvroidis et al., 2012;Sun et al., 2011;Sateesh et al., 2018;Gogikar et al., 2018). CO has relatively longer lifetime. ...
Air pollution occurs when fumes (or smoke) and dust particle gases are introduced into the atmosphere insuch a way that endangers animal and plant. Air pollution harms the health of living beings on our planet.It causes acid rain and smog, which cause respiratory diseases and cancer, depletes the ozone layer, andcontributes to global warming. Current study examines gaseous observations, which is a measure sourceof the air pollution, in an urban National Capital Region of India.The concentration of gases was measuredat air quality monitoring stations (AQMS) located throughout Delhi. The collection is from a five-yearperiod of real-time data observation. Gas variations were interpolated in a geographic information system(GIS) to generate digital elevation models (DEMs). The current study investigated the role of gaseouspollutants in increasing overall pollution levels in Delhi NCR, as well as the variation of gaseous pollutionacross Delhi’s different stations. Temporal interpolation of observations based on the concentration of gasesdepicted on the Z-axis. During the winter and monsoon seasons, distinct clusters of high values are depicted,indicating specific natural and anthropogenic activities. Summer months, on the other hand, indicate lowvalues, indicating steady atmospheric conditions. Such information can play a critical part in enhancingthe government’s developmental initiatives and planning to lower the degree of pollution that our countryrequires.
... Cracker-burning during Diwali has been prevalent for a long time and its impact on pollution levels in Delhi have been observed in previous studies (Sateesh et al., 2018;Singh and Srivastava, 2020). During Diwali festival of 2019 also, the crackers were observed to be burnt and weekly averaged MBC rose significantly around this festival (peak 1 in Fig. 4(b)). ...
... The date of the festival in a particular year varies according to the Hindu lunisolar calendar (Dershowitz and Reingold, 2009). Diwali symbolizes the spiritual victory of light over darkness, good over evil, and wisdom over ignorance (Mathur, 2021), and its celebration involves burning firecrackers and sparklers (Sateesh et al., 2018;Ghei and Sane, 2018). Several festivals in different corners of the world like the New Year celebrations, the Lantern Festival in China, Sky fest in Ireland, and others, include firecrackers (Ambade (2018) and the references therein). ...
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... Global estimates of airborne particulates unanimously identify the Indo-Gangetic Plain (IGP) as amajor aerosol hotspot which, due to its unique regional geomorphology, meteorological variation, and climatic susceptibility, has been a subject for intensive researches in the last few years (Dey et al., 2004;Ramanathan and Feng, 2009;Ramachandran and Kedia, 2010;Saha et al., 2014;Sayer et al., 2014;Chakraborty et al., 2017;Sen et al., 2017;Pratap et al., 2020;Kumar et al., 2020). Under the background of a large increase in anthropogenic emissions during the festival period, haze pollution has also been a common problem over IGP with the degradation of visibility and air quality (Sateesh et al., 2018;Ojha et al., 2020). Chakraborty et al. (2017) have also confirmed that the formation of temperature inversion takes place due to an increase in atmospheric lapse rate that in turn causes inhibition of vertical convection and trapping of air pollutants close to the surface that may enhance the lifetime of those pollutants. ...
Short-term investigations of atmospheric pollutants (PM10, PM2.5, SO2, NO2, O3, and CO) were performed during the Diwali festival over Varanasi for a period of six years from 2011 to 2016. Aerosol Optical Depth (AOD) observed for the corresponding days of Diwali was found to be considerably much higher and even its value reached 2.0 for some Diwali years, which is basically almost 3-folds than the control days. The total scattering aerosol optical thickness as well as aerosol extinction co-efficient at 550 nm crossed the value of 1.0 in almost all the Diwali day cases. The associated meteorological conditions (low wind speed, declining temperature, lowered night-time boundary layer height, etc.) during the Diwali period leads to the detrimental accumulation of atmospheric pollutants near to the surface layer in Varanasi region. Moreover, PM10 and PM2.5 concentrations were recorded much higher than the safer limits set by NAAQS for 24-hour mean values throughout the period of study. The concentrations of PM10 and PM2.5 crossed beyond the safer limits and crossed 500 µg/m³ (in 2015) and 450 µg/m³ (in 2016) respectively, which is basically 5–6 times higher than the standard NAAQS limit. In comparison with the trace gases concentrations (e.g. SO2, NO2, O3, and CO) on control day, it was observed higher on the respective Diwali day. Satellite data derived from MODIS (Aqua and Terra) have also been taken into account to observe and verify the unpropitious effects of fireworks for the chosen case. MODIS true-color images show dense smoke plumes and haze over the entire Indo-Gangetic Plain (IGP) on Diwali days of 2011–2016 with its continuation in the following days. Proper assessment and regular monitoring is needed in order to mitigate the localized air pollution due to this kind of festival by the local scale authority to the top-level environmentalists.
To control and reduce the firework emissions, we report an emerging concept of functional coating materials on fireworks for in-situ generation of encapsulant/adsorbent having potential properties of inhibiting moisture absorption and controlling particulate matter gaseous emissions. The firework sparklers were designed rationally by providing an additional functional coating layer to reduce environmental and chemical footprint and provide a moisture barrier, thus improving the stability and average life compared to their counterpart. The inorganic and organic materials like iron oxide and polyaniline were used as additives and promoters for the in-situ generation of sorbent and encapsulant through multiple transformation chemical reaction steps. The additives and sparkler prepared were investigated thoroughly using different characterization and analysis techniques, including thermogravimetric analysis, surface area, scanning electron microscopy, x-ray diffractometer, inductively coupled plasma optical emission spectroscopy, and moisture analyzer. The functional performance was assessed by determining the combustion sphere and glowing diameter. The in-situ generated encapsulants like ferrites and carbon act as a source of encapsulant and adsorbents, thus facilitating emissions reduction to the tune of 20%–40% and 20%–50% for particulate matter and gaseous emission, respectively.
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Present study deals with an approach to investigate the change in Absorbing Aerosol Index (AAI) within the Indian region using GOME-2 satellite data and the impact of wind speed on AAI using geospatial technique.
This investigation deals with ‘Reduced Emission Green Firecrackers’ to mitigate the adverse impact of fireworks emissions. Two types of sound-emitting green firecrackers, Safe Minimal Aluminium Cracker and Safe Water Releaser, have been developed using zeolite and boric acid hydrogel, respectively. Substantial reduction in usage of chemical oxidizers in sound-emitting firecrackers was achieved with implications on levels of particulate matter and gaseous emissions without detrimental effect on the ignition temperature. The “Green Firecrackers” reported herein possess typical pyrotechnic composition used in conventional crackers, with the only difference being the use of safer and inert additives including zeolite and boric acid hydrogel, which showed positive implications of reduced emissions. In particular, a significant emission reduction of 70–73%, was observed for particulate matter. For gaseous emissions like sulphur oxide and nitrogen oxide, the emissions reduction was tuned down to 50–85% and 25–30% respectively. An insight into possible reasons for reduced emissions in sound crackers reveals that the prevalent mechanisms differs for the type of additive used, which is exemplified by zeolite functioning as i) dust suppressant for particulate matter, ii) sorbent for gaseous emissions and iii) sequestering agent for metal, whereas boric acid hydrogel releases water on ignition which acts as a dust suppressant.
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This study analyzes the spatiotemporal variations of seasonal Moderate Resolution Imaging Spectroradiometer (MODIS) Deep Blue (DB) AOD at 550 nm from the Aqua satellite over Saudi Arabia for the period 2002‒2013. Satellite retrieved AOD is also compared with AERONET AOD over the Solar Village and KAUST station. The result of the seasonal AOD spatial distribution shows that the peak AOD value of 0.6 is observed over Hafr Al Batin, Riyadh, and the Rub Al Khali desert during spring, whereas the Gizan area shows the peak AOD during summer. In contrast, the autumn shows the peak AOD value of 0.5 over Dhahran and in the proximity of Jeddah, whereas Hafr Al Batin, Al Khafji, Al Jubail, and the Rub Al Khali desert show the peak AOD value of 0.4 in winter. Regression analysis shows the AOD increasing trends during spring, summer, and autumn (except for winter) over the entire Saudi Arabia. Over the Solar Village, the AOD increasing trends are also noted during spring and summer, whereas autumn and winter display the AOD decreasing trends. The AOD increasing trends are displayed in all seasons over KAUST. Hence, the AOD increasing/decreasing trends indicate that the number of dust storms either increases or decreases over these regions. Over the Solar Village, the correlation values for MODIS DB AOD versus AERONET AOD are 0.77 (spring), 0.62 (summer), 0.65 (autumn), and 0.75 (winter). Likewise, over KAUST, the correlation values for the same pairing are 0.85 (spring), 0.71 (summer), 0.81 (autumn), and 0.89 (winter). The incorrect aerosol model selection and imperfect surface reflectance calculation are responsible for reducing the correlation. Therefore, this study recommends that the DB algorithm can be used effectively to detect AOD over Saudi Arabia, which will further help to improve the MODIS DB AOD product utilizing the next version of the algorithm.
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Spectral aerosol optical depth (AOD) measurements obtained from multi-wavelength radiometer under cloudless conditions over Doon Valley, in the foothills of the western Himalayas, are analysed during the period January 2007 to December 2012. High AOD values of 0.46 ± 0.08 and 0.52 ± 0.1 at 500 nm, along with low values of Ångström exponent (0.49 ± 0.01 and 0.44 ± 0.03) during spring (March–May) and summer (June–August), respectively, suggest a flat AOD spectrum indicative of coarse-mode aerosol abundance compared with winter (December–February) and autumn (September–November), which are mostly dominated by fine aerosols from urban/industrial emissions and biomass burning. The columnar size distributions (CSD) retrieved from the King’s inversion of spectral AOD exhibit bimodal size patterns during spring and autumn, while combinations of the power-law and unimodal distributions better simulate the retrieved CSDs during winter and summer. High values of extinction coefficient near the surface (∼0.8–1.0 km−1 at 532 nm) and a steep decreasing gradient above are observed via CALIPSO profiles in autumn and winter, while spring and summer exhibit elevated aerosol layers between ∼1.5 and 3.5 km due to the presence of dust. The particle depolarisation ratio shows a slight increasing trend with altitude, with higher values in spring and summer indicative of non-spherical particles of dust origin. The aerosolclimate implications are evaluated via the aerosol radiative forcing (ARF), which is estimated via the synergy of OPAC and SBDART models. On the monthly basis, the ARF values range from ∼ −30 to −90 W m−2 at the surface, while aerosols cause an overall cooling effect at the top of atmosphere (approx. −5 to −15 W m−2). The atmospheric heating via aerosol absorption results in heating rates of 1.2–1.6 K day−1 during March–June, which may contribute to changes in monsoon circulation over northern India and the Himalayas.
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Reduced visibility is an indicator of poor air quality. Moreover, degradation in visibility can be hazardous to human safety; for example, low visibility can lead to road, rail, sea and air accidents. In this paper, we explore the combined influence of atmospheric aerosol particle and gas characteristics, and meteorology, on long-term visibility. We use visibility data from eight meteorological stations, situated in the UK, which have been running since the 1950s. The site locations include urban, rural and marine environments. Most stations show a long-term trend of increasing visibility, which is indicative of reductions in air pollution, especially in urban areas. Additionally, the visibility at all sites shows a very clear dependence on relative humidity, indicating the importance of aerosol hygroscopicity on the ability of aerosol particles to scatter radiation. The dependence of visibility on other meteorological parameters, such as wind speed and wind direction, is also investigated. Most stations show long-term increases in temperature which can be ascribed to climate change, land-use changes (e.g. urban heat island effects) or a combination of both; the observed effect is greatest in urban areas. The impact of this temperature change upon local relative humidity is discussed. To explain the long-term visibility trends and their dependence on meteorological conditions, the measured data were fitted to a newly developed light-extinction model to generate predictions of historic aerosol and gas scattering and absorbing properties. In general, an excellent fit was achieved between measured and modelled visibility for all eight sites. The model incorporates parameterizations of aerosol hygroscopicity, particle concentration, particle scattering, and particle and gas absorption. This new model should be applicable and is easily transferrable to other data sets worldwide. Hence, historical visibility data can be used to assess trends in aerosol particle properties. This approach may help constrain global model simulations which attempt to generate aerosol fields for time periods when observational data are scarce or non-existent. Both the measured visibility and the modelled aerosol properties reported in this paper highlight the success of the UK's Clean Air Act, which was passed in 1956, in cleaning the atmosphere of visibility-reducing pollutants.
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This study evaluates the new Aqua MODIS Dark Target (DT) Collection 6 (C6) Aerosol Optical Depth (AOD) (MYD04_3K) retrieval algorithm at 3 km resolution over Asian countries that have recently experienced severe and increasing air pollution. Retrievals showed generally low accuracy compared with the AErosol RObotic NETwork (AERONET), with only 55% of retrievals within the expected error (EE). The uncertainty appears mainly due to systematic overestimation at both low and high AOD levels. This is attributed to under-prediction of surface reflectance, similar to, but more severe than, the C6 DT product at 10-km resolution. This is because MYD04_3K observes more noise in the surface reflectance computations, due to retention of some bright pixels in the retrieval window which would be discarded at 10 km. Greatest uncertainty was observed at urban sites, especially those dominated by coarse aerosols. Results suggest that the DT at 3 km is less reliable than MODIS C6 AOD products at 10 km.
The " Loy Krathong " festival is a major annual Thai event that includes firework displays. It takes place on the evening of the full moon in the 12th month of the traditional Thai lunar calendar. Since fireworks are widely considered a major source of PAHs, it is considered reasonable to expect a significant increase in PAH levels during this event. The overall PAH profile at the six air quality observatories operated by the Pollution Control Department (PCD), Ministry of Natural Resources and Environment (MNRE), showed that the Kingdom of Thailand's atmosphere was dominated by 5e6-ring PAHs during the firework display period. A significant increase in SPAHs (153%) was observed during firework displays. A statistical analysis coupled with the application of diagnostic binary PAH ratios was conducted to determine whether the detected increase in PAH congeners during the festival period was due to firework combustion or whether it was a coincidental effect caused by vehicular exhausts, long-range atmospheric transportation, photolysis and chemical degradation. The average incremental lifetime cancer risk (ILCR) values of adults and children living in Bangkok as estimated by three different TEQs for ingestion, dermal contact, and inhalation exposure pathways were greatly lesser than the US EPA baseline, further highlighting that the cancer risk of bonfire night falls into the ''acceptable level'' range.
With the launch of NASA's Terra satellite and the MODerate Resolution Imaging Spectroradiometer (MODIS), operational Bidirectional Reflectance Distribution Function (BRDF) and albedo products are now being made available to the scientific community. The MODIS BRDF/Albedo algorithm makes use of a semiempirical kernel-driven bidirectional reflectance model and multidate, multispectral data to provide global 1-km gridded and tiled products of the land surface every 16 days. These products include directional hemispherical albedo (black-sky albedo), bihemispherical albedo (white-sky albedo), Nadir BRDF-Adjusted surface Reflectances (NBAR), model parameters describing the BRDF, and extensive quality assurance information. The algorithm has been consistently producing albedo and NBAR for the public since July 2000. Initial evaluations indicate a stable BRDF/Albedo Product, where, for example, the spatial and temporal progression of phenological characteristics is easily detected in the NBAR and albedo results. These early beta and provisional products auger well for the routine production of stable MODIS-derived BRDF parameters, nadir reflectances, and albedos for use by the global observation and modeling communities.
The present work is aimed to analyze aerosols optical properties and to estimate aerosol radiative forcing (ARF) from January to December 2013, using sky radiometer data over Rohtak, an urban site in North-Western India. The results reveal strong wavelength dependency of aerosol optical depth (AOD), with high values of AOD at shorter wavelengths and lower values at longer wavelength during the study period. The highest AOD values of 1.07 ± 0.45 at 500 nm were observed during July. A significant decline in Ångström exponent was observed during April–May, which represents the dominance of coarse mode particles due to dust-raising convective activities. Aerosols’ size distribution exhibits a bimodal structure with fine mode particles around 0.17 µm and coarse mode particles with a radius around 5.28 µm. Single scattering albedo values were lowest during November–December at all wavelengths, ranging from 0.87 to 0.76, which corresponds to the higher absorption during this period. Aerosols optical properties retrieved during observation period are used as input for SBDART (Santa Barbara DISORT Atmospheric Radiative Transfer) to estimate the direct ARF at the surface, in the atmosphere and at the top of the atmosphere (TOA). The ARF at the TOA, surface and in the atmosphere are found to be in the range of −4.98 to −19.35 W m⁻², −8.01 to −57.66 W m⁻² and +3.02 to +41.64 W m⁻², respectively. The averaged forcing for the whole period of observations at the TOA is −11.26 W m⁻², while at the surface it is −38.64 W m⁻², leading to atmospheric forcing of 27.38 W m⁻². The highest (1.168 K day⁻¹) values of heating rate was estimated during November, whereas the lowest value (0.084 K day⁻¹) was estimated for the February.
Currently, Guangzhou region was facing the problem of severe air pollution. Large amount of aerosols in the polluted air dramatically attenuated solar radiation. This study investigated the vertical optical properties of aerosols and inverted the height of boundary layer in the Guangzhou region using the lidar. Simultaneously, evaluated the impact of different types of clouds on aerosol radiation effects using the SBDART. The results showed that the height of the boundary layer and the surface visibility changed consistently, the average height of the boundary layer on the hazy days was only 61% of that on clear days. At the height of 2 km or lower, the aerosol extinction coefficient profile distribution decreased linearly along with height on clear days, but the haze days saw an exponential decrease. When there was haze, the changing of heating rate of atmosphere caused by the aerosol decreased from 3.72 K/d to 0.9 K/d below the height of 2 km, and the attenuation of net radiation flux at the ground surface was 97.7 W/m2, and the attenuation amplitude was 11.4%; when there were high clouds, the attenuation was 125.2 W/m2 and the attenuation amplitude was 14.6%; where there were medium cloud, the attenuation was 286.4 W/m2 and the attenuation amplitude was 33.4%. Aerosol affected mainly shortwave radiation, and affected long wave radiation very slightly.
A network of air quality and weather monitoring stations was established under the System of Air Quality Forecasting and Research (SAFAR) project in Delhi. We report observations of ozone (O3), nitrogen oxides (NOx), carbon monoxide (CO) and particulate matter (PM2.5 and PM10) before, during and after the Diwali in two consecutive years, i.e., November 2010 and October 2011. The Diwali days are characterised by large firework displays throughout India. The observations show that the background concentrations of particulate matter are between 5 and 10 times the permissible limits in Europe and the United States. During the Diwali-2010, the highest observed PM10 and PM2.5 mass concentration is as high as 2070 µg/m3 and 1620 μg/m3, respectively (24 hr mean), which was about 20 and 27 times to National Ambient Air Quality Standards (NAAQS). For Diwali-2011, the increase in PM10 and PM2.5 mass concentrations was much less with their peaks of 600 and of 390 μg/m3 respectively, as compared to the background concentrations. Contrary to previous reports, firework display was not found to strongly influence the NOx, and O3 mixing ratios, with the increase within the observed variability in the background. CO mixing ratios showed an increase. We show that the large difference in 2010 and 2011 pollutant concentrations is controlled by weather parameters.