Urban residential refuse composition and generation rates for the 20th century.
Examination of historical data shows that 3.5 x 10(8) tonnes (t) of residential refuse was discarded in New York City (NYC) during the 20th century. Maximum and minimum rates of per capita mass discard of residential refuse during this time are reported in 1940 (940 kg per capita yr(-1)) and 1961, 1963 (320 kg per capita yr(-1)), respectively. Since 1980, per capita residential refuse discard rates have been steady and comparatively low (430 kg per capita yr(-1) +/- 2.5%). Fuel ash accounted for approximately 34% of residential refuse in NYC during the century. A decline of refuse bulk density (as collected) from approximately 500 to 200 kg m(-3) and an increase in refuse organic matter content from 20% to 80% (by mass) is reported between 1920 and 1990 and is due largely to mass fraction reductions forfuel ash and increases for paper and plastic. Approximately 4.9 x 10(8) t of refuse was disposed in NYC during the 20th century (including commercial and residential refuse), representing a total pool of about 8.0 x 10(7) t of organic carbon (as C) that has entered city landfills and incinerators.