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Bioaerosols & Indoor Air Quality EMD545b Lecture #8.

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Presentation on theme: "Bioaerosols & Indoor Air Quality EMD545b Lecture #8."— Presentation transcript:

1 Bioaerosols & Indoor Air Quality EMD545b Lecture #8

2 Bioaerosol n Mixture of solid or liquid particles in air containing whole or parts of biological materials. n Biological materials include human pathogens, toxic or allergic pieces of microorganisms, dust mite parts or feces, animal dander, fur, dried saliva, and animal waste products

3 Bioaersols (Examples) n Human pathogens –fungi, bacteria, parasites, viruses n Endotoxin (LPS from gm neg. bacteria) n Mites, animal dander (other allergens) n Fungi –mold –spores –mycotoxins

4 Sick Building Syndrome (SBS)

5 n Acute health and comfort effects experienced by building occupants that are apparently linked to time spent in the building. (EPA) n No specific illness identified n symptoms appear 2-6 hours after entry n symptoms disappear shortly after leaving or overnight (fresh air)

6 Symptoms of SBS –headache –fatigue –shortness of breath –sinus congestion –cough –sneezing –eye, nose, and throat irritation –skin irritation –dizziness, nausea

7 Building Related Illness (BRI) n Illness brought on by exposure to building air. n Symptoms of diagnosable illness identified. n Linked to agents in the air n Examples (Legionnaire’s Disease, Pontiac Fever, Humidifier Fever, Hypersensitivity)

8 Hypersensitivity Diseases n Antigens stimulate antibody response –Hypersensitivity Pneumonitis (IgG produced, Farmer’s Lung) –chills, fever, cough, shortness of breath (4- 8 hours post exposure)

9 Humidifier Fever n Flu-like symptoms (4 - 8 hours post- exposure) n no prominent respiratory symptoms n symptoms dissipate w/in 24 hours n related to cold-aerosol humidifiers in an enclosed space empty water daily, disinfect after use

10 Allergic Rhinitis n Hay fever –nasal obstruction, discharge, post-nasal drip –sneezing, itching, tearing eyes –cough n pollen, mold spores, dust, dander

11 Asthma n Triggers at work –pollen –mites –fungi –insects/arthropods

12 Allergens n Dust mites n Cats, dogs (pets) n Dander (animal facilities) n Cockroaches n Pollen

13 Susceptible Building Occupants n Allergies, asthma n Respiratory disease n Immunosuppressed (patients) n Contact lens wearers n Others?

14 Infectious Diseases n Legionnaire’s Disease –Legionella bacterium growth in water sources 68 - 120 F associated with algae cooling towers, evaporative condensers, spas, plumbing systems, humidifiers –severe pneumonia (5 - 30% mortality) immunosuppressed, those with respiratory conditions at much higher risk –1976 outbreak at American Legion Convention 182 cases, 29 deaths –10,000+ US cases estimated annually

15 Psittacosis n Chlamydia psittaci (bacterium) –fever, chills, headache, muscle aches, fry cough –pneumonia –infection of other organs, can be fatal –< 50 cases/year in US –inhalation of dried secretions from infected birds

16 Aspergillosis n Pneumonia related to inhalation of Aspergillus spores –with fever, cough, chest pain n opportunistic infection in immune suppressed and those with lung disease –Aspergillus fumigatus, A. flavus most common causes –important nosocomial infection –release during construction/renovation work

17 Other Fungal Pathogens n Cryptococcus –Cryptococcus neoformans –isolated from soil worldwide (bird droppings - pigeons) –inhalation of spores –85% of infections among immune deficient –meningitis, permanent neurological damage –12% mortality rate

18 Other Fungal Pathogens n Histoplasmosis –Histoplasma capsulatum –flu-like illness in most (pulmonary involvement of disseminated infection in severe cases) –contaminated soil (bird or bat droppings) –inhalation of spores –immunocompromised at high risk

19 Mycotoxins n Over 200 known n Inhalation, ingestion, skin contact n Aflatoxin B1 (liver cancer, lung cancer?) n Trichothecen mycotoxins –T-2 (inhibits RNA and protein synthesis, toxic to dividing cells, damages variety of organs, tissues, immunosuppressive) –Yellow rain (russian military 1975 - 1981)

20 Fungal Wall Cell Components n Beta (1 - 3) - D- Glucans –small cell wall pieces –inflammatory lung and airway reactions –impair immune system –flu-like illness from high exposures (Organic Dust Toxic Syndrome)

21 Building Assessment n Building History –date of construction –renovations, upgrades new furnishings –meet with building management –list of building activities –previous floods, water damage, leaks

22 Energy Efficient Buildings n 1970’s - Arab oil embargo n construction of “tight” buildings n less use of fresh outdoor air, more re- circulation of treated air n 40% energy cost savings n 99% of requests to NIOSH for air quality investigations occur after 1978

23 Building Assessment n Review of occupant complaints –building location, number of reports –time of complaints (daily or seasonal pattern) –type of complaint health symptoms (acute/chronic) comfort (thermal, odor, noise, lighting) NIOSH 80% rule –input from healthcare professional(s)

24 Building Assessment n Building walkthrough –with building manager –with some occupants (union representation) –complaint areas and non-complaint areas –housekeeping –visible fungal growth (sources of moisture) –overcrowding –fans, blocked diffusers, heaters, humidifiers

25 Hidden Sources of Mold n back side of drywall n top of ceiling tiles (roof leaks) n underside of carpets (carpet below filing cabinets) n pipe chases, utility tunnels n elevator shafts (building syringe) n drain pans in HVAC system n insulation within ductwork

26 Building Assessment n Monitor CO2, dust n Temperature, %RH n Smoke test (airflow) n Amount of fresh air n ASHRAE 62-1999 –20 CFM/person n Odors (volatile chemicals in air)

27 Building Assessment n Review HVAC system –type of system –plenum or ducted system insulation in ductwork? –dirty mechanical room? –preventive maintenance? –% of re-circulated air –time HVAC turned on/off –blocked airflow –odors, stagnant water? –biocides in system?

28 Building HVAC System n Outdoor Air Intake –location (downstream of…) –work in vicinity –pollutants in vicinity bird droppings, decaying matter vehicles, fuel-powered equipment exhaust stacks, toilet exhaust stacks cooling towers, puddles, garbage, etc. –Screens, filters, BIOSECURITY! Air intakes can be used for terrorism events

29 Building HVAC System n Air filtration –filter location –% efficiency –pre-filters? –Maintenance schedule (changes)? –Appearance (excessive dirt/debris) –Fit (leaks around filters - bypass system)

30 Building HVAC System n Supply fan –percentage of fresh air –supply diffusers in rooms (dirt/debris) –air patterns within room (location of supply and exhaust diffusers) short circuiting of air? Poor mixing?

31 Building HVAC System n Heating/cooling coils –condensation drip pans –stagnant water (blocked drains) –sloped toward drain –biocides in use?

32 Building HVAC System n Humidification system –cold water humidification potable, drained off well n Exhaust Fan (discharge from building) –normal, hazard, toilet (separate) –50 ft from supply intakes –at height and velocity to remove from building –no discharge out side of building

33 Bioaerosol Sampling n Develop hypothesis (plan) n Find source and remediate n Sample to assess building, confirm findings n assess occupant exposures

34 Bioaerosol Sampling n Select sampling locations (numbers of samples) –complaint areas, non-complaint areas, outdoors, time of day, year n Sampling method? –Contact (direct microscopic examination) –bulk (bag pieces of suspect material, water) –swab (swipes of suspect surfaces) –air (viable, non-viable methods)

35 Bioaerosol Sampling n Air sampling –non-viable methods (spore traps, filter cassettes) Air-O-Cell –viable methods AGI-30 (all glass impinger - air pumped through liquid medium - good for bacteria) sieve impactors (Anderson Sampler, RCS) Flow rates, calibration critical

36 Bioaerosol Sampling n Select Environmental Microbiology Laboratory accreditation/certification, selection of media incubation temperature for samples? n Sampling Media –viruses, bacteria, parasites, mites, endotoxins TSA, blood agar for bacteria –fungi psychrophyllic, mesophyllic, thermophyllic nutrient requirements (wet, normal conditions) DG-18 (wet), MEA (general)

37 Bioaerosol Sampling n Collection/Transport Protocols –instrument calibration –sterility of media, containers, swabs –disinfection between each use –chain of custody forms –identification of samples field blank, control blank, coded samples –prompt shipment/delivery to lab bacteria samples on ice

38 Bioaerosol Sampling n Enumeration of data –quantity per ml, gm, liter of air, m3 of air, square cm, m2 of surface –quantity of organisms numerator –quantity of media sampled denominator time (min.) x flow rate/min. = total volume (1000 liters per m3 of air)

39 Bioaerosol Sampling n Analysis of data (only snapshot in time) –identification of genus and species –concentration of each per location sampled –rank order indoors vs. outdoors –indoor to outdoor ratio low yield outdoors in colder months –complaint vs. non-complaint areas –immediate notification from lab of serious results –pathogens, positive anthrax, elevated levels in hospitals

40 Standards and Guidelines for Fungi in Indoor Air n No Standards! »Yet too many variables (personal susceptibility and variation among individuals - what levels for sensitized?) »paradichlrobenzene example at Peabody Museum »latex allergy in BWH OR Standards = must Guidelines = should

41 Standards and Guidelines for Fungi in Indoor Air (Rao et al) n Comprehensive review of literature n ACGIH –<100 CFU/m3 = low –100 - 1000 CFU/m3 = intermediate –>1000 CFU/m3 = high n AIHA –>1000 CFU/m3 atypical

42 Standards and Guidelines for Fungi in Indoor Air n General statements –levels indoors should compare with levels outdoors –pathogenic organisms not acceptable in indoor air (WHO, Canada, AIHA) –indoor:outdoor > 1 may (investigate potential indoor source)

43 Remediation n Water = problem! –remove water, dry, clean, disinfect –completely remove mold and dry water- damaged areas –address the source of water or humidity problem –Options discard and replace, wet vacuum, drying (if <24-48 hours), dehumidification, freezing,

44 Remediation n Cleaning can disperse contaminants –don’t sweep, vacuum w/out filtration n damp mop, disinfectant wipe (wet collection methods) n HEPA filtered vacuum cleaners

45 Containment during Remediation or Construction in Sensitive Areas n Sample before project (baseline for clean and contaminated areas) n Communicate to personnel in adjacent areas –scope of work –potential hazards –control measures n Ongoing sampling during project n Final clearance samples (to baseline of clean areas)

46 Containment during Remediation or Construction in Sensitive Areas n Schedule work after hours (evenings, weekends) n Consider closing facility if very sensitive population within/nearby –YPB Medical Oncology n Hire/assign objective, independent project monitors –ensures all workers adhere to protocol –reports problems, breaches immediately –can shut job down on site if necessary

47 Containment during Remediation or Construction in Sensitive Areas n Containment barriers –solid gypsum barriers built (temporary construction) –polyethylene sheeting –anteroom for clothes change –HEPA filtered exhaust fan in contaminated zone create negative pressure gradient within space exhaust only purified air out of space

48 Containment during Remediation or Construction in Sensitive Areas n Personal Protective Equipment –Full jump suits, booties, hood –PAPR or N-100 Disposable respirator or higher –Full face shield (cover all exposed skin) –Tape wrists ankles, etc n Spray contaminated areas with disinfectant before removal –suppress aerosols –decontaminate mold

49 Containment during Remediation or Construction in Sensitive Areas n Collect and seal waste in bags n decontaminate exterior of waste bags n transport out of space in covered cart (exterior also decontaminated) n HEPA vacuum all surfaces after each shift n Disinfect surfaces after shift n Remove and bag PPE after each exit –YPB pizza party

50 Containment during Remediation or Construction in Sensitive Areas n Extensive clearance samples taken n Keep area closed until clearance samples verified clean (below acceptable set point and absence of pathogenic organisms) n Don’t forget to get sanity back after project!


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