Community Air Pollution from Crash Repair Workshops

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					Community Air Pollution from
  Crash Repair Workshops


          Dino Pisaniello
       Department of Public Health
      Adelaide University, Australia
 Background to the public health issue

 Aims and objectives of study

 Project design

 Proximity data

 Stack emission and ground level data

 Implications
Isocyanate
components of
two-pack
polyurethane
paints


Associated with
respiratory
disease
Community concerns about emissions
from spray painting workshops
– odours, potential toxic effects etc.



Australia has one of the highest rates of
asthma


How significant is the issue?
            Objectives

 To identify all crash repair spray painting
  workshops in the Adelaide metropolitan
  area which use (two-pack) isocyanate
  paints.

 To determine and characterise, using
  descriptive statistics, the proximity of
  exhaust stacks to homes and offices.
             Objectives (cont.)
   To quantitatively determine, for a sample of
    workshops:

       stack emissions of isocyanates and solvent vapours,
        with concurrent measurement of meteorological
        variables

       ground level concentrations of isocyanates and solvent
        vapours at various distances from the emission source


   To interpret the public health significance of the
    data by comparison with occupational and
    environmental air quality guidelines.
                       Offices   (n)   %
                        <10m      5    4
Proximity Data          <25m     14    11
                        <50m     43    33
                        none     88    67
n = 131
                       Houses    (n)   %
Other = other small     <10m     13    10
business, factories,    <25m     38    29
shops etc.              <50m     71    54
                        none     60    46

                       Other     (n)   %
                       <10m       22   17
                       <25m       91   69
                       <50m      122   93
                       none       9    7
                   Methods
Isocyanates            (HDI and HDI oligomers)

UK HSE MDHS 25/2
    • using coated glass fibre filters and HPLC UV/EC
    • isokinetic stack sampling

Solvent vapours
(toluene, xylenes, butyl acetate and MEK)
    • charcoal sorbent tubes with GC/FID analysis

Meteorological variables
(wind speed, direction, temperature, humidity)
    • MEA automatic weather station positioned on roof
                  Observations

 Isocyanate spray time is relatively short (2-15% of day)
 Some touch up painting work (usually non-two pack) done
  outside of booth
 There appears to be adequate plume dispersion – the
  plume is seen to rise and disperse
 Workshops rarely use HVLP guns
 Charcoal filters noted for one workshop
                                                   ISOCYANATE CONCENTRATION
                                      Time (min)    (mg NCO/m3)  (mg NCO/m3)
Stack                                                   TWA     during spraying
                  WORKSHOP 1

Isocyanate             Day 1             405            3.0           77
                       Day 2             341            1.4           42

Data              WORKSHOP 2

                       Day 1             339            17            890
                       Day 2             436            11            645

                  WORKSHOP 3
Overall median
= 136 mg NCO/m3        Day 1             334            13            201
                       Day 2             315            11            152
during spraying
                  WORKSHOP 4 (charcoal filter on emissions)


and                    Day 1             362            0.6           13
                       Day 2             260            0.4            8
= 11 mg NCO/m3
                  WORKSHOP 5
as a daily TWA
                       Day 1             361            19            119
                       Day 2             275            66            502
Stack Solvent Concentrations During Spraying


                 Median   Geometric    Range
                 mg/m3      mean       mg/m3
                           mg/m3
 Toluene          25         28        3 - 630
 Xylene           52         43        3 - 402
 Butyl acetate    70         44       0.3 - 523
 MEK              2.6        1.2       0.1-12
Interpretation – Stack Monitoring

ISOCYANATES
Data show isocyanate concentrations to be several times the
STEL while spraying is in progress
i.e. 70 mg NCO/m3
Will depend on the proportion of hardener, isocyanate
content of hardener, gun type, shape and orientation of
object being sprayed, booth exhaust filtration efficiency etc.

SOLVENTS
Total solvent concentrations while spraying:
100 - 1,000 mg/m3
These values approximate STELs
Perimeter Samples

Isocyanates       (HDI and HDI oligomers)

Below the limit of detection
(approx. 0.05 mg NCO/m3)


Solvent vapours
Below the limit of detection
(approx. 0.1 mg/m3) except for one sample
where work was done outside of booth
[3.6 mg/m3 for toluene]
                     Conclusions
   Isocyanate emissions are at hazardous concentrations near the
    stack when spraying is occurring. However, isocyanate spray time
    is relatively short (2-15% of day)
   Ground level (perimeter) concentrations are very low
   There appears to be adequate plume dispersion – the plume is
    seen to rise and disperse
   Solvent vapour concentrations at the stack are at marginally-
    hazardous levels
   Solvent vapours at ground level are very low, but there may be an
    odour depending on wind direction
   Work outside the booth may generate nuisance levels of solvent
    vapour
   The lowest concentration of isocyanates and solvents were found
    for a booth with a charcoal filter

				
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posted:10/1/2012
language:English
pages:14