Daily average concentrations

Particulate Matter. Maximum daily average concentration of particulate matter, smaller than 10 microns, measured at Xalostoc (NW), from July 1989 to July 1990 is exhibited in Figure 4a. The American Standard is 150 /ig m as a daily average. Maximum PMIO concentrations measured in several stations in June 1990 are presented in Figure 4b. 

Figure 4. Particulate matter less than 10 microns (PM 10). (a) Maximum daily average concentration observed at Xalostoc Station (northwest), (b) Maximum daily average concentration observed at five stations in June 1990.

Fig. 2 Daily average concentrations of PM , organic carbon, and levoglucosan at an urban background site in Helsinki from March 2006 to February 2007. The elevated concentrations in April to May and in August are due to wildfires. The increase in levoglucosan concentrations during fall and winter is caused by wood burning in domestic heating...

Fig. 9.7 Simulated solid line) and observed (diamonds) PM 10 daily average concentrations for the (a, c) first (0 +24) and (b, d) second (+24 +48) day of forecast at two Torino urban background stations (a, b) Consolata and (c, d) Gaidano. The comparison refers to June 2006 -January 2007 time period...

It may be seen that, in summertime in many rural areas of Europe, ambient daily average concentrations of ozone regularly reach concentrations more than twice what might be considered natural background levels, i.e. with no anthropogenic sources. Peak hourly concentrations can be ten times higher. 

Zone modelled had 10,000 houses and was calibrated using the statistical distributions shown in Figure 10.7. Daily average concentrations were calculated for all simulated houses. 

The ACGIH recommended maximum time-weighted average concentration in the workplace atmosphere for eight-hour daily exposure is 10 ppm. OSHA has set the permissible exposure level at 2 ppm. It maybe desirable to exclude alcohoHcs, persons with chronic disorders of the Hver, kidneys, and central nervous system, and those with nutritional deficiencies from working with chloroform. 

For each of the CS and the QC concentrations the overall mean and standard deviation are compared to the daily averages and SDs from this, variance components for the within-day and day-to-day effects are estimated by subtraction of variances. 

In Hsinchu, Taiwan, the dietary intake of a- and P-endosulfan was studied from June 1996 to April 1997 (Doong and Lee 1999). p-Endosulfan was not detected in any of the 14 different foods studied, including fruits, meats, seafood, and cereal, and a-endosulfan, by contrast, was found in 78 of 149 samples at an average concentration of 2.76 ng/g wet weight. Based on the average Taiwanese diet, the estimated daily intake of a-endosulfan was 6.24x10 " mg body weight/day. 

TLV, the threshold limit value, a safe, average concentration of the toxic material which can be withstood daily for eight hours a day,... 

T e daily average aerosol concentration is 4060 x 10 particles per m with a fluctuation of + 50 percent based on the standard deviation of the mean. The mean particle size likewise shows large variation with a mean of 0.04 + 0.01 ym. There was some evidence in the aerosol analyzer data for major and minor modes in the size distribution as found by George et al. (1980, 1984). The mean diameter of the particles remained constant as seen in the graph. Both Rn-222 and PAEC (WL) values followed similar diurnal patterns. It is reasonable to expect higher WL levels during the morning due both to increase in radon and aerosol concentrations. The mean diurnal PAEC is 0.006 WL for this seven-day period in September. 

The indirect exposure is estimated by the use of FUSES. FUSES estimates concentrations in food and the total daily intake of a substance based on predicted environmental concentrations for (surface) water, groundwater, soil, sediment, and ambient air. The indirect exposure is principally assessed on two spatial scales locally near a point source of the substance, and regionally using averaged concentrations over a larger area. A third spatial scale, the continental scale, is... 

The general population can be exposed to chemical substances in indoor as well as in outdoor (ambient) air via inhalation of vapors, aerosols, and dusts in the air. The term inhalation exposure is defined as the concentration of a substance in inhaled air at the boundary of the body, and is expressed as an average concentration per unit time (e.g., mg/m per day). In order to estimate a daily dose of a substance from the exposure concentration of the substance in the air, the inhalation rate is used. According to US-EPA (1997), the average daily dose (ADD) can be estimated from the exposure concentration by using the following equation ... 

Rats exposed to the vapor of a mixture of hexa- and pentachloronaphtbalene at average concentrations of 1.16 mg/m for 16 hours daily up to 4.5 months showed definite liver injury, whereas 8.8mg/m produced some mortality and severe liver injury. ... 

Nitrofurantoin is well absorbed after ingestion. It is metabolized and excreted so rapidly that no systemic antibacterial action is achieved. The drug is excreted into the urine by both glomerular filtration and tubular secretion. With average daily doses, concentrations of 200 mcg/mL are reached in urine. In renal failure, urine levels are insufficient for antibacterial action, but high blood levels may cause toxicity. Nitrofurantoin is contraindicated in patients with significant renal insufficiency. 

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