Heating with gas can reduce air pollutant emission and therefore becomes a new sort of peak load heatsource. To study the atmospheric environmental impact

we adopted a newly built combined heating system and simulated its pollutant dispersion for centralized and distributed peak heating. The simulations were based on the improved regulatory environmental impact assessment (EIA) guidelines for atmospheric environment. The model developed an algorithm for infillwinddirection simulation and exported pollutant contours for comparisons. Simulation results show that the system's atmospheric environmental impact is related not only to the pollution emission quantity per quantificational heating

but also to the distribution of heat resource in the gas fired boilers. The centralized peak heating has comparatively small environmental impact; for distributed peak heating

the more concentration of gas fired boilers distribution is applied

the more serious environmental impact will be. In addition

the optimum setting proportion of gas fired boilers should be between 0.2 and 0.6 from the perspective of environmental impact.