As a first stage of an applicatian of the Monte Carlo lvlethod to the thermal radiation lrom a flame oi pool (tank) fire, we confirmed the applicabillty of the method and compared the flat fiame (radiator) model and the cylindrical (solid) ffame madel as the model of suriace emitter The local values o{ arrival pTobability (angle factor) of thermal radiation irom the two models calculated by the method agl~ee well with the anes estimated by the thearetical method The arrival probabillty lrom the flat flame model gives generally greater than that estlmated by the cylindrical flame model, hawever, the difference between these two values are not significant In the case of the flat flame model was adopted to estimate the grand level radiation distribution, which gives unreasonable high value far the vicinity of the tank. This results implies that the cylindrical flame model is recommended to the estimation on grand level radiation in the vicinity of the tank.

Amount　of　fall　dust　were　measured　to　investigate　how　far　the　influence　of　road　dust　extends．The　measuring　points　for　decay by　distance　were　located　at 3，13，33，53 and 103 meters　from　the　road・The　measuring　points　for　de￠ay　by　vertical　direction　were 1，2，3，4 and 5 meters　in　height　from　the　ground　located　at　a　distance　of 10 meters　to　road. Increase　in　amount　of　fall　dust　was showed　distinctly　at　near　the　road　in　winter　before　the　law that　prohibited　using　studded　tires．But　amount　of　fall　dust　showed a　steeply　decrease　with　distance　from　the　road， Numerical　model　was　developed　to　simulate　the　diffusion　process　of　fall　dust　from　the　road．It　was　confirmed　that　calculated values　were　in　agreement　with　the　observed　results．It　became　clear　from　the　observed　and　calculated　results　that　fall　dust caused　by　road　traffic　had　the　influence　on　air　pollution　within　the　range　of 30～40 meters　from　the　road．