'Green firecrackers' with reduced barium emissions in particulate matter.

Ambient air quality is affected due to the emission of pollutants on a large scale after the bursting of firecrackers. Traditionally in all firecrackers, barium (Ba) compounds are used as oxidizers and also to impart green colour flame. Combustion products of barium compounds are water soluble and readily absorbed by the body affecting human health. Thus, the inherent risk of Ba pollution due to the bursting of firecrackers has consequent health effects. To reduce the ambient air pollution caused due to burning of conventional firecrackers, CSIR NEERI has developed reduced emission firecrackers (green crackers). This is achieved by reducing the amount of chemicals, barium nitrate, shell size and addition of additives such as zeolite and iron oxide. This study aims to specifically investigate the influence of additives on the level of barium in reduced emission firecrackers. Four types of conventional and reduced emission firecrackers were selected and tested inside a firecracker emission testing facility to check the levels of barium in PM10 and PM2.5. The measured mean concentrations of all types of reduced emission crackers (green crackers) provided by fireworks manufacturers show significantly reduced barium concentration by 30-60% compared to conventional crackers depending on the type of firecrackers, shell size and amount of chemicals used. The possible reason for reduced Ba level is attributed to i) reduced usage of Ba(NO3)2 and ii) formation of heavy density compounds, leading to soil fallout.

Characterization of polycyclic aromatic hydrocarbons in fugitive PM10 emissions from an integrated iron and steel plant.

Fugitive emissions of PM10 (particles <10µm in diameter) and associated polycyclic aromatic hydrocarbons (PAHs) were monitored in the vicinity of coking unit, sintering unit, blast furnace and steel manufacturing unit in an integrated iron and steel plant situated in India. Concentrations of PM10, PM10-bound total PAHs, benzo (a) pyrene, carcinogenic PAHs and combustion PAHs were found to be highest around the sintering unit. Concentrations of 3-ring and 4-ring PAHs were recorded to be highest in the coking unit whereas 5-and 6-ring PAHs were found to be highest in other units. The following indicatory PAHs were identified: indeno (1,2,3-cd) pyrene, dibenzo (a,h) anthracene, benzo (k) fluoranthene in blast furnace unit; indeno (1,2,3-cd) pyrene, dibenzo (a,h) anthracene, chrysene in sintering unit; Anthracene, fluoranthene, chrysene in coking unit and acenaphthene, fluoranthene, fluorene in steel making unit. Total-BaP-TEQ (Total BaP toxic equivalent quotient) and BaP-MEQ (Total BaP mutagenic equivalent quotient) concentration levels ranged from 2.4 to 231.7ng/m(3) and 1.9 to 175.8ng/m(3), respectively. BaP and DbA (dibenzo (a,h) anthracene) contribution to total-BaP-TEQ was found to be the highest.

Source identification of different size fraction of PM10 using factor analysis at residential cum commercial area of Nagpur city.

Particulate size distribution of PM(10) and associated trace metal concentrations has been carried out in residential cum commercial area of Mahal at Nagpur city. Sampling for size fraction of particulate matter was performed during winter season using eight-stage cascade impactor with a pre-separator and toxic metals were analyzed using inductively coupled plasma-optical emission spectroscopy (ICP-OES). The average concentration of PM(10) and fine particulate matter (effective cut of aerodynamic diameter ≤2.2 µm) was found to be 300 and 136.7 µg/m(3), respectively which was exceeding limit of Central Pollution Control Board. Maximum mass concentration of 41 µg/m(3) in size range of 9.0-10.0 µm and minimum mass concentration of 19 µg/m(3) in size range 2.2-3.3 µm was observed. Metals (Sr, Ni and Zn) were found to large proportions in below 0.7 µm particle size and could therefore pass directly into the alveoli region of human respiratory system. Factor analysis results indicated combustion and vehicular emission as the dominant source in fine mode and resuspended dust was dominant in medium mode while crustal along with vehicular source was major in coarse mode of particulate matter.

Inter-laboratory comparison of NO2 and SO2 generated by dynamic dilution system under laboratory conditions: a technical discussion.

A workshop on analytical quality control (AQC) of ambient air quality measurement methods for nitrogen dioxide (NO(2)) and sulphur dioxide (SO(2)) was conducted by Central Pollution Control Board (CPCB) for officials involved in National Ambient Air Quality Monitoring (NAAQM) in India. Concentrations of NO(2) and SO(2) were generated by dynamic dilution system under laboratory conditions at low and high levels and measured using static dilution system and wet chemical methods laid down by CPCB under section 16(2)(h) of the air act 1981. CPCB provided the measured values as reference values for comparing the means obtained by the officials participated from thirteen organizations. A tolerance limit of +/-15% of the reference values was specified to accept the results. Generated concentrations, which were unknown to the participants, were measured using gaseous sampling assembly (Envirotech APM 411, New Delhi, India), and wet chemical methods laid down by CPCB i.e. the same methodology which is used by the organizations to generate the data of NO(2) and SO(2) in ambient air. Simultaneously, concentrations were checked by CPCB using automatic analyzers as a check on reference concentration. It is observed that results of automatic analyzers for NO(2) and SO(2) were within a tolerance of +/-5% with %RSD below 3. On the other hand, results of most of the participants showed variability in the measurements with %RSD ranging between +/-0.8 and +/-88.6 and exceedences of means from the tolerance limit with bias ranging between 1.4 and -59%. To check the cause of high variability in the measurements obtained under identical conditions, duplicate sampling was performed by one of the participants for SO(2) at low concentration level. In this study, results of wet chemical methods, automatic analyzers and results of duplicate sampling are analysed statistically to assess the cause of high variability in the measurements. Analysis of t-test and analysis of variance (ANOVA) showed highly significant results for NO(2) and SO(2) at high concentration levels (alpha 0.05) and for SO(2) at both the levels (alpha 0.01) respectively indicating some bias is existing either in the sampling or in analytical technique. Duplicate sampling performed to check precision in parallel measurements showed high %RSD indicating the presence of systematic error in sampling technique as the same calibration factor (CF) was used to measure the concentration of duplicate samples. Statistical analysis of flow rates of duplicate sampling showed that the sampling assembly could not maintain the constant flow rate within the +/-10% with that measured at the start of the sampling. This resulted in high %RSD and deviation from the reference values for the results of most of the participants, even after accepting +/-15% tolerance limit. There is a need to improve and evaluate this gaseous sample collection device under laboratory conditions to generate reliable database of NO(2) and SO(2) in ambient air.