Emissions from South Asian brick production

Thirteen South Asian brick kilns were tested to quantify aerosol and gaseous pollutant emissions. Particulate matter (PM_2.5), carbon monoxide (CO), and optical scattering and absorption measurements in the exhaust of six kiln technologies demonstrate differences in overall emission profiles and relative climate warming resulting from kiln design and fuel choice. Emission factors differed between kiln types, in some cases by an order of magnitude. The kilns currently dominating the sector had the highest emission factors of PM_2.5 and light absorbing carbon, while improved Vertical Shaft and Tunnel kilns were lower emitters. An improved version of the most common technology in the region, the zig-zag kiln, was among the lowest emitting kilns in PM_2.5, CO, and light absorbing carbon. Emission factors measured here are lower than those currently used in emission inventories as inputs to global climate models; 85% lower (PM_2.5) and 35% lower for elemental carbon (EC) for the most common kiln in the region, yet the ratio of EC to total carbon was higher than previously estimated (0.96 compared to 0.47). Total annual estimated emissions from the brick industry are 120 Tg CO ₂, 2.5 Tg CO, 0.19 Tg PM_2.5, and 0.12 Tg EC.