Calcium CO-Amendments Modify Extractable Orthophosphate Levels in Fresh and Composted Cattle Manure

The Hong Kong Environmental ProtectionDepartment (HK EPD) monitoring data for SO₂, NO, NO₂and O₃ from 1995 and 1996 at three stations spanning thelength of Hong Kong have been analyzed in the contexts ofselected meteorological parameters, and the types of synopticweather system. High level and episode days were definedaccording to two criteria. Higher pollutant gas concentrationswere found for systems involving the transport of continentalair masses to Hong Kong (cold front (type CF), north/northeastmonsoon (type NE)), or when tropical cyclones approached (typeAC) Hong Kong. Lower concentrations were observed when thecleaner maritime southerly (type S) airstreams were incidentat Hong Kong. Most notably, tropical cyclones (type C)ventilated and diluted local pollution. Days with high levelsof SO₂, NO and NO₂ were generally characterized bylow windspeed and lower relative humidity conditions. Bycontrast, high concentrations of O₃ occurred both underlow windspeed conditions (type AC) and under the advection ofa continental air mass, generally at high windspeeds. Thediurnal variation of O₃ levels is discussed: destructionis more important than production in determining local levels.