雨中主要杂质浓度表

                  杂质                                      来源                                       地点                 正常范围（1X10^-3mg/m³）
                 NH₄                  矿物燃料，森林有机物的腐烂             海洋空气             0.04-0.29
                                                                                                               内陆空气               0.10-0.76
                   
                  NO₃                             工业过程及内燃机                      海洋空气             0.3-5
                                                                                                               内陆空气              0.10-0.6

                 CL                        海盐，土壤颗粒海洋空气                  海洋空气             0.10-0.5
                                                                                                               内陆空气            1-20